C-H Stretching in Alkane, Alkene, and Alkyne IR

Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching bands in infrared, or IR, spectra. These bands help identify how the carbon atoms are hybridized. The bond type affects the stretching frequency that appears in the spectrum.

The difference comes from s characte...

The IR stretching frequency of a C–H bond depends on the hybridization of the carbon atom.

An sp³ hybridized carbon displays the lowest C–H stretching frequency. The frequency increases for the C–H with an sp² carbon, followed by an sp carbon.

This is because an sp-hybrid or...